Typically, a motor for an automotive vehicle includes electro-mechanical-brake (EMB) assembly used to power electro mechanical brakes, also known as electric brake calipers. Typically, the electro mechanical brakes, utilize an electric motor positioned relative to a caliper housing to drive through intervening planetary or other gears, which act as a force multiplier, an inline rotatable ballscrew of a ballscrew subassembly positioned within the caliper housing. The rotating ballscrew linearly moves a ballnut of the ballscrew subassembly. The ballnut is connected to and linearly moves an inner brake pad against a brake rotor of the automotive vehicle.
An outer brake pad, mounted to the caliper housing, is positioned on an opposite side of the brake rotor. Therefore, during braking, the inner brake pad will be forced against the rotor and a resulting reactionary force will pull the outer brake pad into engagement with the opposite side of the rotor. Engagement of the inner and outer brake pads with the rotor will slow and stop the vehicle or hold a stopped vehicle in a fixed position. To set the brake as a parking brake, a separate electric motor is used to move a locking mechanism into engagement with a latch gear attached to a drive shaft of the EMB electric motor. This separate electric motor requires extra space thereby disadvantageously diminishing packaging characteristics of the EMB assembly.
Alluding to the above, various electric motor assemblies are currently used in the automotive industry. Such assemblies are disclosed in the U.S. Pat. No. 5,549,183 to Buchanan, Jr. et al.; U.S. Pat. No. 5,949,168 to Dieckmann et al; U.S. Pat. No. 5,765,671 to Endo et al.; U.S. Pat. No. 6,000,489 to Rick; U.S. Pat. No. 6,089,360 to Borgardt; U.S. Pat. No. 6,269,917 to Harting et al.; and U.S. Pat. No. 6,744,162 to Pierre et al. Other prior art designs tried to solve the aforementioned disadvantages by implementing a design, which eliminates the need for the separate electric motor but does not improve magnetic flux path between latching components of the EMB assembly such as a spring and an electromagnetic device necessary for efficient latching engagement between the motor shaft and the caliper housing.
Accordingly, there is a need for a park brake system having a mechanism positioned therein with the park brake system having improved packaging characteristics and improved latching or meshing engagement between the components of the park brake system.